Dave Plowman (News) wrote:
In article ,
Tim S Kemp wrote:
One FreeView moan. Some radio services peak to 0dBFS. TV sound only to
-10dBFS. Many older progs on the 'minority' channels to considerably
less than -10. So switching from TV sound to radio can result in a
*vast* change in level.

I'd noticed this but not gone so far as to measure it...

Has always seemed odd to me that different stations have different
requirements for peak recorded level - in the digital age surely we
should be mastering to 0dbFS.

The problem is that when digital came in, EU broadcasting settled on a
line up level of -18dBFS. Analogue machines using the same line up levels
were approx 8dB below peak (depending on many things). But analogue tape
overloads fairly gracefully, while digital doesn't, so it was decided to
leave 10dB headroom above nominal peak level. And this got transferred to
FreeView TV sound.

Pop radio however is never happy unless their modulation levels are at
near constant peak.

It shouldn't be forgotten either that audio levels are still being
monitored with a standard BBC PPM which under reads by anything between
4 and 8 dB on very short-term peaks, so 10dB of headroom on digital
transmission is sensible. In spite of many attempts, I could never
persuade anyone at either the BBC or commercial operators to adopt a
true-peak PPM, even one with the same standard 1-7 scale. Those who
tried it always went back to the well-known and loved quasi-peak as it
looked more like they were used to.

S.

In article ,
Serge Auckland wrote:
It shouldn't be forgotten either that audio levels are still being
monitored with a standard BBC PPM which under reads by anything between
4 and 8 dB on very short-term peaks, so 10dB of headroom on digital
transmission is sensible.

I very much doubt anything goes to line without going through a
compressor/limiter, and all such things tend to remove the sort of peaks
that fool a PPM.

In spite of many attempts, I could never persuade anyone at either the
BBC or commercial operators to adopt a true-peak PPM, even one with the
same standard 1-7 scale. Those who tried it always went back to the
well-known and loved quasi-peak as it looked more like they were used
to.

Thing is that the ear can't really hear these short term peaks, so the
meter not reading them is no bad thing from a balance - if not engineering
- point of view.

I've got fast acting peak LEDs on the workshop PPM and they're on most of
the time. ;-)

--
*The average person falls asleep in seven minutes *

Dave Plowman London SW
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